(a) Field of the Invention
This invention relates to a computed radiography (CR) system which employs a light collector such as a bundle of optical fibers. More particularly, this invention relates to a computed radiography (CR) system employing a bundle of optical fibers for collecting and transferring luminescence light, having a linear end and a two-dimensional end in which a plurality of optical fibers are sequentially arranged according to an input order of light.
(b) Description of the Related Art
In recent years, computed radiography (CR) systems have been successful in replacing analog screen/film (SF) in many clinical settings. Such CR systems use photostimulable x-ray storage phosphor plates (for example, BaFBr:Eu.sup.2+), which are exposed in cassettes and then brought to an automated plate scanner providing with a bundle of optical fibers for collecting and transferring light, to read out the stored image information.
CR systems bring numerous advantages such as electronic transmission and storage, image processing, and computer-aided diagnosis to clinical departments, in a practical and highly affordable way. However, technical progress in the CR field has reached a plateau (perhaps in part because of economic developments at the chemical imaging companies who originally supported the development of the technology), and CR image quality performance has been surpassed by flat-panel based digital radiography (DR) systems.
DR systems, however, are much more expensive than CR, which has limited their clinical acceptance. A single CR reader can support multiple cassettes and replacing the SF cassettes with CR cassettes can retrofit an entire radiology department. Each individual detector in a room requires a separate DR detector. Furthermore, the replacement cost for a worn out or broken DR detector can be ten to one hundred times more expensive than replacing a CR cassette.
The image quality performance of CR has been limited in the past by two factors: (1) Because of limitations in screen conversion gain, collection efficiency, and detection efficiency, in a CR system that is not optimally designed, the number of detected electrons per absorbed x-ray (“gain”) can become low enough to become a secondary quantum sink, (2) CR systems have been observed to have rather high gain fluctuation noise, or “Swank noise”, compared to high quality SF or DR systems, where “the Swank noise” can degrade DQE performance and is quantified by the optical Swank factor, which is induced by depth-dependent variations in optical gain.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.